This research builds on the foundation of several recent investigations that have explored the interface between health and mental health services, and that have examined the detection of mental disorders by primry care physicians. The proposed research will examine the effects of a recent health policy decision in Santa Barbara, California, which has mandated that specialist services (including mental health care) provided to Medi-Cal clients be formally sanctioned by their primary care physicians, the "gatekeepers" to these services. The designated physicians operate in two very different contexts, one an organized health care setting (Santa Barbara County Health Care Services) and the other a cooperative arrangement between autonomous health professionals. The proposed research will compare the diagnostic skills and referral behaviors of physicians in each context (vis-a-vis psychiatric disturbances). It will also implement an intervention for a randomly selected group of the physicians in each context to influence their mental illness recognition and referral patterns. Finally, an assessment will be undertaken of the effects of this health policy on mental health outcomes and on referral and liaison services by means of semi-structured interviews with the primary care physicians and the mental health specialists in each system. The theoretical implications of this research will reside primarily with an increased understanding of the appropriateness of assigning primary care physicians to the role of "gatekeepers" to mental health services. The findings will have further implications for conceptualizing the interface and boundaries between health and mental health professions among geographically diverse providers and among those in integrated delivery settings. Finally, the results will speak to the likely impact of interventions designed to increase the effectiveness of primary care physicians in this "gatekeeper" role, and to the type and quality of mental health care that may be provided within such systems.